#include <bits/stdc++.h> #define MaxSize 100 /* * Created by HarvestWu on 2018/06/19. */ using namespace std; typedef char ElemType; //定义二叉树结构 typedef struct BTNode { ElemType data; struct BTNode *lchild; struct BTNode *rchild; } BTNode; //定义存储结点指针及层号结构 typedef struct St { BTNode *p; int lno; } St; //由str串创建二树 void CreateBTNode (BTNode *&b,ElemType *str) { BTNode *St[MaxSize],*p= NULL; int top=-1, k = 0,j=0; ElemType ch; b= NULL; ch=str[j]; while (ch!='\0') { switch (ch) { case '(': top++; St[top]=p; k=1; break; case ')': top--; break; case ',': k=2; break; default: p=(BTNode *)malloc(sizeof(BTNode)); p->data=ch; p->lchild=p->rchild= NULL; if (b== NULL) b=p; else { switch(k) { case 1: St[top]->lchild=p; break; case 2: St[top]->rchild=p; break; default: break; } } } j++; ch=str[j]; } } //递归先序遍历 void preOrder(BTNode *p) { if (p!= NULL) { cout<<p->data<<" "; preOrder(p->lchild); preOrder(p->rchild); } } //非递归先序遍历 void preOrderNonRecursion(BTNode *p) { if (p!= NULL) { BTNode *Stack[MaxSize]; int top=-1; BTNode *q; Stack[++top]=p; while(top!=-1) { q=Stack[top--]; cout<<q->data<<" "; if(q->rchild!=NULL) Stack[++top]=q->rchild; if(q->lchild!=NULL) Stack[++top]=q->lchild; } } } //递归中序遍历 void inOrder(BTNode *p) { if (p!= NULL) { inOrder(p->lchild); cout<<p->data<<" "; inOrder(p->rchild); } } //非递归中序遍历 void inOrderNonRecursion(BTNode *p) { if(p!=NULL) { BTNode *Stack[MaxSize]; int top=-1; BTNode *q; q=p; while(top!=-1||q!=NULL) { while(q!=NULL) { Stack[++top]=q; q=q->lchild; } if(top!=-1) { q=Stack[top--]; cout<<q->data<<" "; q=q->rchild; } } } } //递归后序遍历 void postOrder(BTNode *p) { if (p!= NULL) { postOrder(p->lchild); postOrder(p->rchild); cout<<p->data<<" "; } } //非递归后序遍历 void postOrderNonRecursion(BTNode *p) { if (p!= NULL) { BTNode *Stack1[MaxSize],*Stack2[MaxSize]; int top1=-1,top2=-1; BTNode *q; Stack1[++top1]=p; while(top1!=-1) { q=Stack1[top1--]; Stack2[++top2]=q; if(q->lchild!=NULL) Stack1[++top1]=q->lchild; if(q->rchild!=NULL) Stack1[++top1]=q->rchild; } while(top2!=-1) { q=Stack2[top2--]; cout<<q->data<<" "; } } } //求二叉树深度 int getDepth(BTNode *p) { int LD,RD; if(p==NULL) return 0; else { LD=getDepth(p->lchild); RD=getDepth(p->rchild); return (LD>RD?LD:RD)+1; } } //寻找二叉树中是否存在某值节点 void searchBTNode(BTNode *p,BTNode *&q,int key) { if(p!=NULL) { if(p->data==key) q=p; else { searchBTNode(p->lchild,q,key); searchBTNode(p->rchild,q,key); } } } //层序遍历 void level(BTNode *p) { int front,rear; BTNode *que[MaxSize]; front=rear=0; BTNode *q; if (p!=NULL) { rear=(rear+1)%MaxSize; que[rear]=p; while (front!=rear) { front=(front+1)%MaxSize; q=que[front]; cout<<q->data<<" "; if (q->lchild!=NULL) { rear=(rear+1)%MaxSize; que[rear]=q->lchild; } if(q->rchild!=NULL) { rear=(rear+1)%MaxSize; que[rear]=q->rchild; } } } } //求二叉树宽度 int maxNode(BTNode *b) { St que[MaxSize]; int front,rear; int Lno,i,j,n,max; front=rear=0; BTNode *q; if (b!=NULL) { ++rear; que[rear].p=b; que[rear].lno=1; while (front!=rear) { ++front; q=que[front].p; Lno=que[front].lno; if(q->lchild!=NULL) { ++rear; que[rear].p=q->lchild; que[rear].lno=Lno+1; } if(q->rchild!=NULL) { ++rear; que[rear].p=q->rchild; que[rear].lno=Lno+1; } } max=0; for(i=1; i<=Lno; ++i) { n=0; for(j=1; j<rear; ++j) { if(que[j].lno==i) ++n; } if(max<n) max=n; } return max; } else return 0; } int main() { BTNode *b,*p,*lp,*rp;; CreateBTNode(b,"A(B(D,E(H(J,K(L,M(,N))))),C(F,G(,I)))"); cout<<"递归先序遍历:"<<endl; preOrder(b); cout<<"\n非递归先序遍历:"<<endl; preOrderNonRecursion(b); cout<<"\n递归中序遍历:"<<endl; inOrder(b); cout<<"\n非递归中序遍历:"<<endl; inOrderNonRecursion(b); cout<<"\n递归后序遍历:"<<endl; postOrder(b); cout<<"\n非递归后序遍历:"<<endl; postOrderNonRecursion(b); cout<<"\n二叉树深度:"<<endl; cout<<getDepth(b); cout<<"\n寻找二叉树中是否存在某值节点:"<<endl; searchBTNode(b,p,'A'); cout<<p->data; cout<<"\n层序遍历:"<<endl; level(b); cout<<"\n二叉树宽度:"<<endl; cout<<maxNode(b)<<endl; return 0; } 文章来源: C++ 二叉树的遍历